OpenApi 3.1 - Naive implementation of Schema dereference

[char0n]

Subject of this issue is naive implementation of JSON Schema 2020 dereference.

For this naive implementation we're assuming following:

• value of $ref is JSON Pointer, URI or URI with fragment part containing JSON pointer
• merging is processed according to following behavior; outer has higher priority then inner
• referencing a possible non-schema has following behavior; we always assume referenced fragment is another schema if the document is generic ApiDOM

Todo

• POC implementation
• Tests

Problems:

• freezing of ApiDOM will no longer be possible as with schema dereferencing acyclic directed tree becomes cyclic directed graph